[llvm] [AArch64][SME] Introduce CHECK_MATCHING_VL pseudo for streaming transitions (PR #157510)

[Benjamin Maxwell via llvm-commits]

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@@ -0,0 +1,335 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve,+sme,+sme2p1 < %s -o - | FileCheck %s
+
+target triple = "aarch64-unknown-linux-gnu"
+
+declare void @bar_enabled(<vscale x 4 x i32>) #0
+
+; Non-streaming -> calls streaming callee
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MacDue wrote:

Can we have a test where the check needs to be after the `smstop` (e.g. streaming -> non-streaming). I see that occurs in some other tests, but I'd be good to have all examples in once place. 

https://github.com/llvm/llvm-project/pull/157510